Dr. Coppari said the insulin levels of the animals treated with the placebo solution rose increasingly higher post-surgery. "That's a normal outcome because insulin sensitivity decreases the longer you keep an animal on a high-fat diet."

Insulin levels in the mice given resveratrol, however, actually started to drop and were halfway to normal by the end of the five-week study period, even though the animals remained on a high-fat diet.

In addition, the researchers found that resveratrol did indeed activate sirtuin proteins in the brain.

Dr. Coppari said the findings support his team's theory that the brain plays a vital role in mediating the beneficial effects of resveratrol and that manipulation of brain sirtuins also may have other beneficial outcomes. "By knowing that the central nervous system is involved, pharmaceutical companies can begin to focus on developing drugs that selectively target sirtuins in the brain," he said.

The next step, Dr. Coppari said, is to determine precisely which neurons in the brain are mediating the effects of the resveratrol.

Other UT Southwestern researchers involved in the study include Drs. Giorgio Ramadori, Laurent Gautron and Teppei Fujikawa, postdoctoral researchers in internal medicine; Dr. Claudia Vianna, instructor of internal medicine; and Dr. Joel Elmquist, professor of internal medicine and director of the Center for Hypothalamic Research at UT Southwestern.

Source: UT Southwestern Medical Center